docs: def _emiss_ep(self, Eph):
          """
          Electron-proton bremsstrahlung emissivity per unit photon energy
          """
          if self.weight_ep == 0.0:
              return np.zeros_like(Eph)
  
          gam = np.vstack(self._gam)
          eps = (Eph / mec2).decompose().value
          # compute integral with electron distribution
          emiss = c.cgs * trapz_loglog(
              np.vstack(self._nelec) * self._sigma_ep(gam, eps),
              self._gam,
              axis=0,
          ).to(u.cm ** 2 / Eph.unit)
          return emiss